Patients with poor risk all ages 1-9 with initial white blood cells counts more than 50,000/ul or ages between 10 years and 21 years are eligible. All patients will receive BFM induction. A day 7 marrow classify subjects as either rapid early responsdoners, slow responders whose cells are CD19+ will be randomized to continued on BFM induction with and without the addition of immunotoxin (B43-PAP).